I actually managed to get in on the website, almost by accident. Turkish wouldn't take the reservation ID (even the one that Aeroplan gave me for Turkish), but I ended up getting in with a ticket number, once I realized that I actually had three different ticket numbers (one Air Canada, one for Swiss/Lufthansa, and one for Turkish), and I just tried them all until one worked - I ended up finding that by going in to my reservation on the Aeroplan website, since the e-ticket/itinerary I was emailed only had the first (Air Canada) ticket number, not all three.